Guinness sent me the following criteria, which I referred to when getting evaluated and measured by medical staff.

"GUIDELINES FOR LONGEST TONGUE

In order to be measured, the claimant must stick his/her tongue out as far as is
comfortably possible, and then have it measured from the tip to the middle of
the closed upper lip.

Three measurements must be taken on one occasion and the average of the
three will be the accepted figure.

The measurements should be done by qualified medical practitioners,
physiologists, a member of Guinness World Records or similar.

The name of the person being measured should be given, along with the date
and place.

Medical statements must be provided, these must state the measurements.

Video and photographic evidence of the measurement taking place must be
submitted."

I gave you a copy of the medical statement in SF, but I'll email another just to be sure, as well as the full video of the medical evaluation.

And Stephen Taylor of the UK actually had his tongue Measured at 9.8 cm and should be considered longest by them currently... As I'm about to send in my documentation :D Chanel Tapper with her massive tongue holds the record for women.